The present invention relates to a flasher type fish sonar having a light emitting diode for displaying, a receiving portion for receiving display signals, a rotary disk position detecting portion, and a power receiving coil mounted on the rotary disk.
In prior flasher type fish sonar, a display disk comprises a circular window formed at a front of a case, and a luminous body is mounted to a rotary disk opposite to the circular window. The rotary disk is rotated by a motor, slip rings are attached to a rotary shaft of the rotary disk, and brushes contact the slip rings. An input circuit is connected to the brushes, a control circuit is connected to the input circuit, and an oscillating circuit and a receiving circuit are connected to the control circuit and an ultrasonic transducer.
When oscillating signals are input from the control circuit to the oscillating circuit, oscillating outputs are input from the oscillating circuit to the ultrasonic transducer, and ultrasonic waves are emitted from the ultrasonic vibrator to the water. Reflected ultrasonic waves from the water are received by the ultrasonic transducer, and reflected signals from the ultrasonic transducer are amplified by the receiving circuit and are input from the control circuit to the input circuit. By the reflected signals applied to the input circuit, luminous power is input to the luminous body through the brushes and slip rings from the input circuit. A portion A displayed on the circular window is a start point of a luminosity which shows a surface of the sea, portion B shows fishes, a portion C shows a first bottom echo of the sea, and a portion D shows a second bottom echo of the sea.
In the prior flasher type fish sonar, because power and display signals are supplied by brushes and slip rings, a large vibration and noise are generated and brushes are worn by the wear.